Improvements for coroutine creation

- Keep track of the number of created and destroyed coroutines for each
   computer.
 - Run coroutines with a thread pool executor, which will keep stale
   threads around for 60 seconds. This substantially reduces the
   pressure from short-lived coroutines.
 - Update to the latest Cobalt version.

build.gradle

@@ -66,7 +66,7 @@ dependencies {
 
     runtime "mezz.jei:jei_1.12.2:4.8.5.159"
 
-    shade 'org.squiddev:Cobalt:0.3.2'
+    shade 'org.squiddev:Cobalt:0.4.0'
 
     testCompile 'junit:junit:4.11'
 

src/main/java/dan200/computercraft/core/apis/http/HTTPExecutor.java

@@ -24,7 +24,7 @@ public final class HTTPExecutor
     public static final ListeningExecutorService EXECUTOR = MoreExecutors.listeningDecorator( new ThreadPoolExecutor(
         4, Integer.MAX_VALUE,
         60L, TimeUnit.SECONDS,
-        new SynchronousQueue<Runnable>(),
+        new SynchronousQueue<>(),
         new ThreadFactoryBuilder()
             .setDaemon( true )
             .setPriority( Thread.MIN_PRIORITY + (Thread.NORM_PRIORITY - Thread.MIN_PRIORITY) / 2 )

src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java

@@ -6,15 +6,14 @@
 
 package dan200.computercraft.core.lua;
 
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.*;
-import dan200.computercraft.api.lua.ILuaObject;
-import dan200.computercraft.api.lua.ILuaTask;
-import dan200.computercraft.api.lua.LuaException;
-import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.core.computer.Computer;
 import dan200.computercraft.core.computer.ITask;
 import dan200.computercraft.core.computer.MainThread;
+import dan200.computercraft.core.tracking.Tracking;
+import dan200.computercraft.core.tracking.TrackingField;
 import org.squiddev.cobalt.*;
 import org.squiddev.cobalt.compiler.CompileException;
 import org.squiddev.cobalt.compiler.LoadState;
@@ -25,7 +24,7 @@ import org.squiddev.cobalt.function.LibFunction;
 import org.squiddev.cobalt.function.LuaFunction;
 import org.squiddev.cobalt.function.VarArgFunction;
 import org.squiddev.cobalt.lib.*;
-import org.squiddev.cobalt.lib.platform.AbstractResourceManipulator;
+import org.squiddev.cobalt.lib.platform.VoidResourceManipulator;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
@@ -35,6 +34,9 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.Map;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 
 import static org.squiddev.cobalt.Constants.NONE;
 import static org.squiddev.cobalt.ValueFactory.valueOf;
@@ -42,6 +44,16 @@ import static org.squiddev.cobalt.ValueFactory.varargsOf;
 
 public class CobaltLuaMachine implements ILuaMachine
 {
+    private static final ThreadPoolExecutor coroutines = new ThreadPoolExecutor(
+        0, Integer.MAX_VALUE,
+        60L, TimeUnit.SECONDS,
+        new SynchronousQueue<>(),
+        new ThreadFactoryBuilder()
+            .setDaemon( true )
+            .setNameFormat( "ComputerCraft-Coroutine-%d" )
+            .build()
+    );
+
     private final Computer m_computer;
 
     private final LuaState m_state;
@@ -57,15 +69,9 @@ public class CobaltLuaMachine implements ILuaMachine
         m_computer = computer;
 
         // Create an environment to run in
-        final LuaState state = this.m_state = new LuaState( new AbstractResourceManipulator()
+        LuaState state = this.m_state = LuaState.builder()
-        {
+            .resourceManipulator( new VoidResourceManipulator() )
-            @Override
+            .debug( new DebugHandler()
-            public InputStream findResource( String filename )
-            {
-                return null;
-            }
-        } );
-        state.debug = new DebugHandler( state )
             {
                 private int count = 0;
                 private boolean hasSoftAbort;
@@ -76,7 +82,7 @@ public class CobaltLuaMachine implements ILuaMachine
                     int count = ++this.count;
                     if( count > 100000 )
                     {
-                    if( m_hardAbortMessage != null ) LuaThread.yield( state, NONE );
+                        if( m_hardAbortMessage != null ) LuaThread.yield( m_state, NONE );
                         this.count = 0;
                     }
                     else
@@ -90,19 +96,22 @@ public class CobaltLuaMachine implements ILuaMachine
                 @Override
                 public void poll() throws LuaError
                 {
-                if( m_hardAbortMessage != null ) LuaThread.yield( state, NONE );
+                    if( m_hardAbortMessage != null ) LuaThread.yield( m_state, NONE );
                     handleSoftAbort();
                 }
 
-            private void handleSoftAbort() throws LuaError {
+                private void handleSoftAbort() throws LuaError
+                {
                     // If the soft abort has been cleared then we can reset our flags and continue.
                     String message = m_softAbortMessage;
-                if (message == null) {
+                    if( message == null )
+                    {
                         hasSoftAbort = false;
                         return;
                     }
 
-                if (hasSoftAbort && m_hardAbortMessage == null) {
+                    if( hasSoftAbort && m_hardAbortMessage == null )
+                    {
                         // If we have fired our soft abort, but we haven't been hard aborted then everything is OK.
                         return;
                     }
@@ -110,7 +119,21 @@ public class CobaltLuaMachine implements ILuaMachine
                     hasSoftAbort = true;
                     throw new LuaError( message );
                 }
-        };
+            } )
+            .coroutineFactory( command -> {
+                Tracking.addValue( m_computer, TrackingField.COROUTINES_CREATED, 1 );
+                coroutines.execute( () -> {
+                    try
+                    {
+                        command.run();
+                    }
+                    finally
+                    {
+                        Tracking.addValue( m_computer, TrackingField.COROUTINES_DISPOSED, 1 );
+                    }
+                } );
+            } )
+            .build();
 
         m_globals = new LuaTable();
         state.setupThread( m_globals );

src/main/java/dan200/computercraft/core/tracking/TrackingField.java

@@ -28,6 +28,9 @@ public class TrackingField
     public static final TrackingField WEBSOCKET_INCOMING = TrackingField.of( "websocket_incoming", "Websocket incoming", TrackingField::formatBytes );
     public static final TrackingField WEBSOCKET_OUTGOING = TrackingField.of( "websocket_outgoing", "Websocket outgoing", TrackingField::formatBytes );
 
+    public static final TrackingField COROUTINES_CREATED = TrackingField.of( "coroutines_created", "Coroutines created", x -> String.format( "%4d", x ) );
+    public static final TrackingField COROUTINES_DISPOSED = TrackingField.of( "coroutines_dead", "Coroutines disposed", x -> String.format( "%4d", x ) );
+
     private final String id;
     private final String displayName;
     private final LongFunction<String> format;